If you are looking for a place to have a meal with the best view in London, I'll suggest Dim-T. The pricing is just as great as the location and for these 2 reasons, it has been my best restaurant in London for years. If you are just after the food and nothing else there are several other branches around London that you can visit.
Their coconut rice is so yummy, I can literally eat it on its own. The food at this restaurant is mainly asian but is also infused with european bits and bobs.